crypto/io/skein_mod.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://opensource.org/licenses/CDDL-1.0.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2013 Saso Kiselkov. All rights reserved.
 */

#include <sys/modctl.h>
#include <sys/crypto/common.h>
#include <sys/crypto/spi.h>
#include <sys/strsun.h>
#include <sys/sysmacros.h>
#include <sys/systm.h>
#define SKEIN_MODULE_IMPL
#include <sys/skein.h>

/*
 * Like the sha2 module, we create the skein module with two modlinkages:
 * - modlmisc to allow direct calls to Skein_* API functions.
 * - modlcrypto to integrate well into the Kernel Crypto Framework (KCF).
 */
static struct modlmisc modlmisc = {
    &mod_miscops,
    "Skein Message-Digest Algorithm"
};

static struct modlcrypto modlcrypto = {
    &mod_cryptoops,
    "Skein Kernel SW Provider"
};

static struct modlinkage modlinkage = {
    MODREV_1, &modlmisc, &modlcrypto, NULL
};

static crypto_mech_info_t skein_mech_info_tab[] = {
    {CKM_SKEIN_256, SKEIN_256_MECH_INFO_TYPE,
        CRYPTO_FG_DIGEST | CRYPTO_FG_DIGEST_ATOMIC,
        0, 0, CRYPTO_KEYSIZE_UNIT_IN_BITS},
    {CKM_SKEIN_256_MAC, SKEIN_256_MAC_MECH_INFO_TYPE,
        CRYPTO_FG_MAC | CRYPTO_FG_MAC_ATOMIC, 1, INT_MAX,
        CRYPTO_KEYSIZE_UNIT_IN_BYTES},
    {CKM_SKEIN_512, SKEIN_512_MECH_INFO_TYPE,
        CRYPTO_FG_DIGEST | CRYPTO_FG_DIGEST_ATOMIC,
        0, 0, CRYPTO_KEYSIZE_UNIT_IN_BITS},
    {CKM_SKEIN_512_MAC, SKEIN_512_MAC_MECH_INFO_TYPE,
        CRYPTO_FG_MAC | CRYPTO_FG_MAC_ATOMIC, 1, INT_MAX,
        CRYPTO_KEYSIZE_UNIT_IN_BYTES},
    {CKM_SKEIN1024, SKEIN1024_MECH_INFO_TYPE,
        CRYPTO_FG_DIGEST | CRYPTO_FG_DIGEST_ATOMIC,
        0, 0, CRYPTO_KEYSIZE_UNIT_IN_BITS},
    {CKM_SKEIN1024_MAC, SKEIN1024_MAC_MECH_INFO_TYPE,
        CRYPTO_FG_MAC | CRYPTO_FG_MAC_ATOMIC, 1, INT_MAX,
        CRYPTO_KEYSIZE_UNIT_IN_BYTES}
};

static void skein_provider_status(crypto_provider_handle_t, uint_t *);

static crypto_control_ops_t skein_control_ops = {
    skein_provider_status
};

static int skein_digest_init(crypto_ctx_t *, crypto_mechanism_t *,
    crypto_req_handle_t);
static int skein_digest(crypto_ctx_t *, crypto_data_t *, crypto_data_t *,
    crypto_req_handle_t);
static int skein_update(crypto_ctx_t *, crypto_data_t *, crypto_req_handle_t);
static int skein_final(crypto_ctx_t *, crypto_data_t *, crypto_req_handle_t);
static int skein_digest_atomic(crypto_provider_handle_t, crypto_session_id_t,
    crypto_mechanism_t *, crypto_data_t *, crypto_data_t *,
    crypto_req_handle_t);

static crypto_digest_ops_t skein_digest_ops = {
    skein_digest_init,
    skein_digest,
    skein_update,
    NULL,
    skein_final,
    skein_digest_atomic
};

static int skein_mac_init(crypto_ctx_t *, crypto_mechanism_t *, crypto_key_t *,
    crypto_spi_ctx_template_t, crypto_req_handle_t);
static int skein_mac_atomic(crypto_provider_handle_t, crypto_session_id_t,
    crypto_mechanism_t *, crypto_key_t *, crypto_data_t *, crypto_data_t *,
    crypto_spi_ctx_template_t, crypto_req_handle_t);

static crypto_mac_ops_t skein_mac_ops = {
    skein_mac_init,
    NULL,
    skein_update,   /* using regular digest update is OK here */
    skein_final,    /* using regular digest final is OK here */
    skein_mac_atomic,
    NULL
};

static int skein_create_ctx_template(crypto_provider_handle_t,
    crypto_mechanism_t *, crypto_key_t *, crypto_spi_ctx_template_t *,
    size_t *, crypto_req_handle_t);
static int skein_free_context(crypto_ctx_t *);

static crypto_ctx_ops_t skein_ctx_ops = {
    skein_create_ctx_template,
    skein_free_context
};

static crypto_ops_t skein_crypto_ops = {
    &skein_control_ops,
    &skein_digest_ops,
    NULL,
    &skein_mac_ops,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    &skein_ctx_ops,
    NULL,
    NULL,
    NULL
};

static crypto_provider_info_t skein_prov_info = {
    CRYPTO_SPI_VERSION_4,
    "Skein Software Provider",
    CRYPTO_SW_PROVIDER,
    {&modlinkage},
    NULL,
    &skein_crypto_ops,
    sizeof (skein_mech_info_tab) / sizeof (crypto_mech_info_t),
    skein_mech_info_tab
};

static crypto_kcf_provider_handle_t skein_prov_handle = 0;

typedef struct skein_ctx {
    skein_mech_type_t       sc_mech_type;
    size_t              sc_digest_bitlen;
    union {
        Skein_256_Ctxt_t    sc_256;
        Skein_512_Ctxt_t    sc_512;
        Skein1024_Ctxt_t    sc_1024;
    } sc_u;
} skein_ctx_t;
#define SKEIN_CTX(_ctx_)    ((skein_ctx_t *)((_ctx_)->cc_provider_private))
#define SKEIN_CTX_LVALUE(_ctx_) (_ctx_)->cc_provider_private
#define SKEIN_OP(_skein_ctx, _op, ...)                  \
    do {                                \
        skein_ctx_t *sc = (_skein_ctx);         \
        switch (sc->sc_mech_type) {             \
        case SKEIN_256_MECH_INFO_TYPE:              \
        case SKEIN_256_MAC_MECH_INFO_TYPE:          \
            (void) Skein_256_ ## _op(&sc->sc_u.sc_256,  \
                __VA_ARGS__);               \
            break;                      \
        case SKEIN_512_MECH_INFO_TYPE:              \
        case SKEIN_512_MAC_MECH_INFO_TYPE:          \
            (void) Skein_512_ ## _op(&sc->sc_u.sc_512,  \
                __VA_ARGS__);               \
            break;                      \
        case SKEIN1024_MECH_INFO_TYPE:              \
        case SKEIN1024_MAC_MECH_INFO_TYPE:          \
            (void) Skein1024_ ## _op(&sc->sc_u.sc_1024, \
                __VA_ARGS__);               \
            break;                      \
        }                           \
        _NOTE(CONSTCOND)                    \
    } while (0)

static int
skein_get_digest_bitlen(const crypto_mechanism_t *mechanism, size_t *result)
{
    if (mechanism->cm_param != NULL) {
        /*LINTED(E_BAD_PTR_CAST_ALIGN)*/
        skein_param_t   *param = (skein_param_t *)mechanism->cm_param;

        if (mechanism->cm_param_len != sizeof (*param) ||
            param->sp_digest_bitlen == 0) {
            return (CRYPTO_MECHANISM_PARAM_INVALID);
        }
        *result = param->sp_digest_bitlen;
    } else {
        switch (mechanism->cm_type) {
        case SKEIN_256_MECH_INFO_TYPE:
            *result = 256;
            break;
        case SKEIN_512_MECH_INFO_TYPE:
            *result = 512;
            break;
        case SKEIN1024_MECH_INFO_TYPE:
            *result = 1024;
            break;
        default:
            return (CRYPTO_MECHANISM_INVALID);
        }
    }
    return (CRYPTO_SUCCESS);
}

int
_init(void)
{
    int error;

    if ((error = mod_install(&modlinkage)) != 0)
        return (error);

    /*
     * Try to register with KCF - failure shouldn't unload us, since we
     * still may want to continue providing misc/skein functionality.
     */
    (void) crypto_register_provider(&skein_prov_info, &skein_prov_handle);

    return (0);
}

int
_info(struct modinfo *modinfop)
{
    return (mod_info(&modlinkage, modinfop));
}

/*
 * KCF software provider control entry points.
 */
/* ARGSUSED */
static void
skein_provider_status(crypto_provider_handle_t provider, uint_t *status)
{
    *status = CRYPTO_PROVIDER_READY;
}

/*
 * General Skein hashing helper functions.
 */

/*
 * Performs an Update on a context with uio input data.
 */
static int
skein_digest_update_uio(skein_ctx_t *ctx, const crypto_data_t *data)
{
    off_t       offset = data->cd_offset;
    size_t      length = data->cd_length;
    uint_t      vec_idx;
    size_t      cur_len;
    const uio_t *uio = data->cd_uio;

    /* we support only kernel buffer */
    if (uio->uio_segflg != UIO_SYSSPACE)
        return (CRYPTO_ARGUMENTS_BAD);

    /*
     * Jump to the first iovec containing data to be
     * digested.
     */
    for (vec_idx = 0; vec_idx < uio->uio_iovcnt &&
        offset >= uio->uio_iov[vec_idx].iov_len;
        offset -= uio->uio_iov[vec_idx++].iov_len)
        ;
    if (vec_idx == uio->uio_iovcnt) {
        /*
         * The caller specified an offset that is larger than the
         * total size of the buffers it provided.
         */
        return (CRYPTO_DATA_LEN_RANGE);
    }

    /*
     * Now do the digesting on the iovecs.
     */
    while (vec_idx < uio->uio_iovcnt && length > 0) {
        cur_len = MIN(uio->uio_iov[vec_idx].iov_len - offset, length);
        SKEIN_OP(ctx, Update, (uint8_t *)uio->uio_iov[vec_idx].iov_base
            + offset, cur_len);
        length -= cur_len;
        vec_idx++;
        offset = 0;
    }

    if (vec_idx == uio->uio_iovcnt && length > 0) {
        /*
         * The end of the specified iovec's was reached but
         * the length requested could not be processed, i.e.
         * The caller requested to digest more data than it provided.
         */
        return (CRYPTO_DATA_LEN_RANGE);
    }

    return (CRYPTO_SUCCESS);
}

/*
 * Performs a Final on a context and writes to a uio digest output.
 */
static int
skein_digest_final_uio(skein_ctx_t *ctx, crypto_data_t *digest,
    crypto_req_handle_t req)
{
    off_t   offset = digest->cd_offset;
    uint_t  vec_idx;
    uio_t   *uio = digest->cd_uio;

    /* we support only kernel buffer */
    if (uio->uio_segflg != UIO_SYSSPACE)
        return (CRYPTO_ARGUMENTS_BAD);

    /*
     * Jump to the first iovec containing ptr to the digest to be returned.
     */
    for (vec_idx = 0; offset >= uio->uio_iov[vec_idx].iov_len &&
        vec_idx < uio->uio_iovcnt;
        offset -= uio->uio_iov[vec_idx++].iov_len)
        ;
    if (vec_idx == uio->uio_iovcnt) {
        /*
         * The caller specified an offset that is larger than the
         * total size of the buffers it provided.
         */
        return (CRYPTO_DATA_LEN_RANGE);
    }
    if (offset + CRYPTO_BITS2BYTES(ctx->sc_digest_bitlen) <=
        uio->uio_iov[vec_idx].iov_len) {
        /* The computed digest will fit in the current iovec. */
        SKEIN_OP(ctx, Final,
            (uchar_t *)uio->uio_iov[vec_idx].iov_base + offset);
    } else {
        uint8_t *digest_tmp;
        off_t scratch_offset = 0;
        size_t length = CRYPTO_BITS2BYTES(ctx->sc_digest_bitlen);
        size_t cur_len;

        digest_tmp = kmem_alloc(CRYPTO_BITS2BYTES(
            ctx->sc_digest_bitlen), crypto_kmflag(req));
        if (digest_tmp == NULL)
            return (CRYPTO_HOST_MEMORY);
        SKEIN_OP(ctx, Final, digest_tmp);
        while (vec_idx < uio->uio_iovcnt && length > 0) {
            cur_len = MIN(uio->uio_iov[vec_idx].iov_len - offset,
                length);
            bcopy(digest_tmp + scratch_offset,
                uio->uio_iov[vec_idx].iov_base + offset, cur_len);

            length -= cur_len;
            vec_idx++;
            scratch_offset += cur_len;
            offset = 0;
        }
        kmem_free(digest_tmp, CRYPTO_BITS2BYTES(ctx->sc_digest_bitlen));

        if (vec_idx == uio->uio_iovcnt && length > 0) {
            /*
             * The end of the specified iovec's was reached but
             * the length requested could not be processed, i.e.
             * The caller requested to digest more data than it
             * provided.
             */
            return (CRYPTO_DATA_LEN_RANGE);
        }
    }

    return (CRYPTO_SUCCESS);
}

/*
 * Performs an Update on a context with mblk input data.
 */
static int
skein_digest_update_mblk(skein_ctx_t *ctx, crypto_data_t *data)
{
    off_t offset = data->cd_offset;
    size_t length = data->cd_length;
    mblk_t *mp;
    size_t cur_len;

    /* Jump to the first mblk_t containing data to be digested. */
    for (mp = data->cd_mp; mp != NULL && offset >= MBLKL(mp);
        offset -= MBLKL(mp), mp = mp->b_cont)
        ;
    if (mp == NULL) {
        /*
         * The caller specified an offset that is larger than the
         * total size of the buffers it provided.
         */
        return (CRYPTO_DATA_LEN_RANGE);
    }

    /* Now do the digesting on the mblk chain. */
    while (mp != NULL && length > 0) {
        cur_len = MIN(MBLKL(mp) - offset, length);
        SKEIN_OP(ctx, Update, mp->b_rptr + offset, cur_len);
        length -= cur_len;
        offset = 0;
        mp = mp->b_cont;
    }

    if (mp == NULL && length > 0) {
        /*
         * The end of the mblk was reached but the length requested
         * could not be processed, i.e. The caller requested
         * to digest more data than it provided.
         */
        return (CRYPTO_DATA_LEN_RANGE);
    }

    return (CRYPTO_SUCCESS);
}

/*
 * Performs a Final on a context and writes to an mblk digest output.
 */
static int
skein_digest_final_mblk(skein_ctx_t *ctx, crypto_data_t *digest,
    crypto_req_handle_t req)
{
    off_t   offset = digest->cd_offset;
    mblk_t  *mp;

    /* Jump to the first mblk_t that will be used to store the digest. */
    for (mp = digest->cd_mp; mp != NULL && offset >= MBLKL(mp);
        offset -= MBLKL(mp), mp = mp->b_cont)
        ;
    if (mp == NULL) {
        /* caller specified offset is too large */
        return (CRYPTO_DATA_LEN_RANGE);
    }

    if (offset + CRYPTO_BITS2BYTES(ctx->sc_digest_bitlen) <= MBLKL(mp)) {
        /* The digest will fit in the current mblk. */
        SKEIN_OP(ctx, Final, mp->b_rptr + offset);
    } else {
        /* Split the digest up between the individual buffers. */
        uint8_t *digest_tmp;
        off_t scratch_offset = 0;
        size_t length = CRYPTO_BITS2BYTES(ctx->sc_digest_bitlen);
        size_t cur_len;

        digest_tmp = kmem_alloc(CRYPTO_BITS2BYTES(
            ctx->sc_digest_bitlen), crypto_kmflag(req));
        if (digest_tmp == NULL)
            return (CRYPTO_HOST_MEMORY);
        SKEIN_OP(ctx, Final, digest_tmp);
        while (mp != NULL && length > 0) {
            cur_len = MIN(MBLKL(mp) - offset, length);
            bcopy(digest_tmp + scratch_offset,
                mp->b_rptr + offset, cur_len);
            length -= cur_len;
            mp = mp->b_cont;
            scratch_offset += cur_len;
            offset = 0;
        }
        kmem_free(digest_tmp, CRYPTO_BITS2BYTES(ctx->sc_digest_bitlen));
        if (mp == NULL && length > 0) {
            /* digest too long to fit in the mblk buffers */
            return (CRYPTO_DATA_LEN_RANGE);
        }
    }

    return (CRYPTO_SUCCESS);
}

/*
 * KCF software provider digest entry points.
 */

/*
 * Initializes a skein digest context to the configuration in `mechanism'.
 * The mechanism cm_type must be one of SKEIN_*_MECH_INFO_TYPE. The cm_param
 * field may contain a skein_param_t structure indicating the length of the
 * digest the algorithm should produce. Otherwise the default output lengths
 * are applied (32 bytes for Skein-256, 64 bytes for Skein-512 and 128 bytes
 * for Skein-1024).
 */
static int
skein_digest_init(crypto_ctx_t *ctx, crypto_mechanism_t *mechanism,
    crypto_req_handle_t req)
{
    int error = CRYPTO_SUCCESS;

    if (!VALID_SKEIN_DIGEST_MECH(mechanism->cm_type))
        return (CRYPTO_MECHANISM_INVALID);

    SKEIN_CTX_LVALUE(ctx) = kmem_alloc(sizeof (*SKEIN_CTX(ctx)),
        crypto_kmflag(req));
    if (SKEIN_CTX(ctx) == NULL)
        return (CRYPTO_HOST_MEMORY);

    SKEIN_CTX(ctx)->sc_mech_type = mechanism->cm_type;
    error = skein_get_digest_bitlen(mechanism,
        &SKEIN_CTX(ctx)->sc_digest_bitlen);
    if (error != CRYPTO_SUCCESS)
        goto errout;
    SKEIN_OP(SKEIN_CTX(ctx), Init, SKEIN_CTX(ctx)->sc_digest_bitlen);

    return (CRYPTO_SUCCESS);
errout:
    bzero(SKEIN_CTX(ctx), sizeof (*SKEIN_CTX(ctx)));
    kmem_free(SKEIN_CTX(ctx), sizeof (*SKEIN_CTX(ctx)));
    SKEIN_CTX_LVALUE(ctx) = NULL;
    return (error);
}

/*
 * Executes a skein_update and skein_digest on a pre-initialized crypto
 * context in a single step. See the documentation to these functions to
 * see what to pass here.
 */
static int
skein_digest(crypto_ctx_t *ctx, crypto_data_t *data, crypto_data_t *digest,
    crypto_req_handle_t req)
{
    int error = CRYPTO_SUCCESS;

    ASSERT(SKEIN_CTX(ctx) != NULL);

    if (digest->cd_length <
        CRYPTO_BITS2BYTES(SKEIN_CTX(ctx)->sc_digest_bitlen)) {
        digest->cd_length =
            CRYPTO_BITS2BYTES(SKEIN_CTX(ctx)->sc_digest_bitlen);
        return (CRYPTO_BUFFER_TOO_SMALL);
    }

    error = skein_update(ctx, data, req);
    if (error != CRYPTO_SUCCESS) {
        bzero(SKEIN_CTX(ctx), sizeof (*SKEIN_CTX(ctx)));
        kmem_free(SKEIN_CTX(ctx), sizeof (*SKEIN_CTX(ctx)));
        SKEIN_CTX_LVALUE(ctx) = NULL;
        digest->cd_length = 0;
        return (error);
    }
    error = skein_final(ctx, digest, req);

    return (error);
}

/*
 * Performs a skein Update with the input message in `data' (successive calls
 * can push more data). This is used both for digest and MAC operation.
 * Supported input data formats are raw, uio and mblk.
 */
/*ARGSUSED*/
static int
skein_update(crypto_ctx_t *ctx, crypto_data_t *data, crypto_req_handle_t req)
{
    int error = CRYPTO_SUCCESS;

    ASSERT(SKEIN_CTX(ctx) != NULL);

    switch (data->cd_format) {
    case CRYPTO_DATA_RAW:
        SKEIN_OP(SKEIN_CTX(ctx), Update,
            (uint8_t *)data->cd_raw.iov_base + data->cd_offset,
            data->cd_length);
        break;
    case CRYPTO_DATA_UIO:
        error = skein_digest_update_uio(SKEIN_CTX(ctx), data);
        break;
    case CRYPTO_DATA_MBLK:
        error = skein_digest_update_mblk(SKEIN_CTX(ctx), data);
        break;
    default:
        error = CRYPTO_ARGUMENTS_BAD;
    }

    return (error);
}

/*
 * Performs a skein Final, writing the output to `digest'. This is used both
 * for digest and MAC operation.
 * Supported output digest formats are raw, uio and mblk.
 */
/*ARGSUSED*/
static int
skein_final(crypto_ctx_t *ctx, crypto_data_t *digest, crypto_req_handle_t req)
{
    int error = CRYPTO_SUCCESS;

    ASSERT(SKEIN_CTX(ctx) != NULL);

    if (digest->cd_length <
        CRYPTO_BITS2BYTES(SKEIN_CTX(ctx)->sc_digest_bitlen)) {
        digest->cd_length =
            CRYPTO_BITS2BYTES(SKEIN_CTX(ctx)->sc_digest_bitlen);
        return (CRYPTO_BUFFER_TOO_SMALL);
    }

    switch (digest->cd_format) {
    case CRYPTO_DATA_RAW:
        SKEIN_OP(SKEIN_CTX(ctx), Final,
            (uint8_t *)digest->cd_raw.iov_base + digest->cd_offset);
        break;
    case CRYPTO_DATA_UIO:
        error = skein_digest_final_uio(SKEIN_CTX(ctx), digest, req);
        break;
    case CRYPTO_DATA_MBLK:
        error = skein_digest_final_mblk(SKEIN_CTX(ctx), digest, req);
        break;
    default:
        error = CRYPTO_ARGUMENTS_BAD;
    }

    if (error == CRYPTO_SUCCESS)
        digest->cd_length =
            CRYPTO_BITS2BYTES(SKEIN_CTX(ctx)->sc_digest_bitlen);
    else
        digest->cd_length = 0;

    bzero(SKEIN_CTX(ctx), sizeof (*SKEIN_CTX(ctx)));
    kmem_free(SKEIN_CTX(ctx), sizeof (*(SKEIN_CTX(ctx))));
    SKEIN_CTX_LVALUE(ctx) = NULL;

    return (error);
}

/*
 * Performs a full skein digest computation in a single call, configuring the
 * algorithm according to `mechanism', reading the input to be digested from
 * `data' and writing the output to `digest'.
 * Supported input/output formats are raw, uio and mblk.
 */
/*ARGSUSED*/
static int
skein_digest_atomic(crypto_provider_handle_t provider,
    crypto_session_id_t session_id, crypto_mechanism_t *mechanism,
    crypto_data_t *data, crypto_data_t *digest, crypto_req_handle_t req)
{
    int     error;
    skein_ctx_t skein_ctx;
    crypto_ctx_t    ctx;
    SKEIN_CTX_LVALUE(&ctx) = &skein_ctx;

    /* Init */
    if (!VALID_SKEIN_DIGEST_MECH(mechanism->cm_type))
        return (CRYPTO_MECHANISM_INVALID);
    skein_ctx.sc_mech_type = mechanism->cm_type;
    error = skein_get_digest_bitlen(mechanism, &skein_ctx.sc_digest_bitlen);
    if (error != CRYPTO_SUCCESS)
        goto out;
    SKEIN_OP(&skein_ctx, Init, skein_ctx.sc_digest_bitlen);

    if ((error = skein_update(&ctx, data, digest)) != CRYPTO_SUCCESS)
        goto out;
    if ((error = skein_final(&ctx, data, digest)) != CRYPTO_SUCCESS)
        goto out;

out:
    if (error == CRYPTO_SUCCESS)
        digest->cd_length =
            CRYPTO_BITS2BYTES(skein_ctx.sc_digest_bitlen);
    else
        digest->cd_length = 0;
    bzero(&skein_ctx, sizeof (skein_ctx));

    return (error);
}

/*
 * Helper function that builds a Skein MAC context from the provided
 * mechanism and key.
 */
static int
skein_mac_ctx_build(skein_ctx_t *ctx, crypto_mechanism_t *mechanism,
    crypto_key_t *key)
{
    int error;

    if (!VALID_SKEIN_MAC_MECH(mechanism->cm_type))
        return (CRYPTO_MECHANISM_INVALID);
    if (key->ck_format != CRYPTO_KEY_RAW)
        return (CRYPTO_ARGUMENTS_BAD);
    ctx->sc_mech_type = mechanism->cm_type;
    error = skein_get_digest_bitlen(mechanism, &ctx->sc_digest_bitlen);
    if (error != CRYPTO_SUCCESS)
        return (error);
    SKEIN_OP(ctx, InitExt, ctx->sc_digest_bitlen, 0, key->ck_data,
        CRYPTO_BITS2BYTES(key->ck_length));

    return (CRYPTO_SUCCESS);
}

/*
 * KCF software provide mac entry points.
 */
/*
 * Initializes a skein MAC context. You may pass a ctx_template, in which
 * case the template will be reused to make initialization more efficient.
 * Otherwise a new context will be constructed. The mechanism cm_type must
 * be one of SKEIN_*_MAC_MECH_INFO_TYPE. Same as in skein_digest_init, you
 * may pass a skein_param_t in cm_param to configure the length of the
 * digest. The key must be in raw format.
 */
static int
skein_mac_init(crypto_ctx_t *ctx, crypto_mechanism_t *mechanism,
    crypto_key_t *key, crypto_spi_ctx_template_t ctx_template,
    crypto_req_handle_t req)
{
    int error;

    SKEIN_CTX_LVALUE(ctx) = kmem_alloc(sizeof (*SKEIN_CTX(ctx)),
        crypto_kmflag(req));
    if (SKEIN_CTX(ctx) == NULL)
        return (CRYPTO_HOST_MEMORY);

    if (ctx_template != NULL) {
        bcopy(ctx_template, SKEIN_CTX(ctx),
            sizeof (*SKEIN_CTX(ctx)));
    } else {
        error = skein_mac_ctx_build(SKEIN_CTX(ctx), mechanism, key);
        if (error != CRYPTO_SUCCESS)
            goto errout;
    }

    return (CRYPTO_SUCCESS);
errout:
    bzero(SKEIN_CTX(ctx), sizeof (*SKEIN_CTX(ctx)));
    kmem_free(SKEIN_CTX(ctx), sizeof (*SKEIN_CTX(ctx)));
    return (error);
}

/*
 * The MAC update and final calls are reused from the regular digest code.
 */

/*ARGSUSED*/
/*
 * Same as skein_digest_atomic, performs an atomic Skein MAC operation in
 * one step. All the same properties apply to the arguments of this
 * function as to those of the partial operations above.
 */
static int
skein_mac_atomic(crypto_provider_handle_t provider,
    crypto_session_id_t session_id, crypto_mechanism_t *mechanism,
    crypto_key_t *key, crypto_data_t *data, crypto_data_t *mac,
    crypto_spi_ctx_template_t ctx_template, crypto_req_handle_t req)
{
    /* faux crypto context just for skein_digest_{update,final} */
    int     error;
    crypto_ctx_t    ctx;
    skein_ctx_t skein_ctx;
    SKEIN_CTX_LVALUE(&ctx) = &skein_ctx;

    if (ctx_template != NULL) {
        bcopy(ctx_template, &skein_ctx, sizeof (skein_ctx));
    } else {
        error = skein_mac_ctx_build(&skein_ctx, mechanism, key);
        if (error != CRYPTO_SUCCESS)
            goto errout;
    }

    if ((error = skein_update(&ctx, data, req)) != CRYPTO_SUCCESS)
        goto errout;
    if ((error = skein_final(&ctx, mac, req)) != CRYPTO_SUCCESS)
        goto errout;

    return (CRYPTO_SUCCESS);
errout:
    bzero(&skein_ctx, sizeof (skein_ctx));
    return (error);
}

/*
 * KCF software provider context management entry points.
 */

/*
 * Constructs a context template for the Skein MAC algorithm. The same
 * properties apply to the arguments of this function as to those of
 * skein_mac_init.
 */
/*ARGSUSED*/
static int
skein_create_ctx_template(crypto_provider_handle_t provider,
    crypto_mechanism_t *mechanism, crypto_key_t *key,
    crypto_spi_ctx_template_t *ctx_template, size_t *ctx_template_size,
    crypto_req_handle_t req)
{
    int     error;
    skein_ctx_t *ctx_tmpl;

    ctx_tmpl = kmem_alloc(sizeof (*ctx_tmpl), crypto_kmflag(req));
    if (ctx_tmpl == NULL)
        return (CRYPTO_HOST_MEMORY);
    error = skein_mac_ctx_build(ctx_tmpl, mechanism, key);
    if (error != CRYPTO_SUCCESS)
        goto errout;
    *ctx_template = ctx_tmpl;
    *ctx_template_size = sizeof (*ctx_tmpl);

    return (CRYPTO_SUCCESS);
errout:
    bzero(ctx_tmpl, sizeof (*ctx_tmpl));
    kmem_free(ctx_tmpl, sizeof (*ctx_tmpl));
    return (error);
}

/*
 * Frees a skein context in a parent crypto context.
 */
static int
skein_free_context(crypto_ctx_t *ctx)
{
    if (SKEIN_CTX(ctx) != NULL) {
        bzero(SKEIN_CTX(ctx), sizeof (*SKEIN_CTX(ctx)));
        kmem_free(SKEIN_CTX(ctx), sizeof (*SKEIN_CTX(ctx)));
        SKEIN_CTX_LVALUE(ctx) = NULL;
    }

    return (CRYPTO_SUCCESS);
}